Gas-fired portable heaters are well known in the art and are used in multiple environments. The heater typically includes a housing having a chamber. The housing has an inlet for receiving air into the chamber. Gas is introduced into the chamber to be mixed with the air in order to complete combustion and provide an infrared heating surface. A plenum directs the heat toward a mesh screen and distributes it over the surface thereof.
The use of such heaters is strictly regulated for outdoor only use due to the emission of carbon monoxide and other potentially harmful combustion products. Prior designs in existing portable units are subject to a wide variety of problems. The prior designs are not safe or certified to operate in small recreational enclosures such as tents, truck-caps, fishing huts, trailers, vans, etc. There are many reasons why the devices found in the prior art are not adequate to perform in such environments. Some previous designs do not have the ability to meet safety regulations regarding combustion requirements at a high and low firing condition and at a reduced pressure. Some designs do not possess an oxygen depletion system (“ODS”). Some designs do not measure or respond to undesirable carbon dioxide levels. These shortcomings have prevented many portable heaters from adequately performing in small recreational and temporary work enclosures.
Therefore, it remains desirable to provide a portable gas-fired heater capable of performing safely in small recreational enclosures and temporary work enclosures.